The colonies of certain species of ants, for example Pogonomyrmex barbatus, exhibit changes in behaviour as the colonies grow older, despite nearly all of the individual ants being replaced each year [1]. The behaviour of older colonies is more stable, and they are more likely to avoid intraspecific conflict [2]. Gordon hypothesised that the reason for this is that a 3-4 year old colony is in t...

While reproductive caste in eusocial insects is usually determined by environmental factors, in some populations of the harvester ants, Pogonomyrmex barbatus and P. rugosus, caste has been shown to have a strong genetic component. This system of genetic caste determination (GCD) is characterized by between-caste nuclear variation and high levels of mitochondrial haplotype variation between alte...

We examined the effect of queen size on the probability of new colony establishment in the ant Pogonomyrmex occidentalis. Large queens are significantly more likely to survive than small queens through the initial stages of colony founding. These differences in individual fitness correlates have corresponding effects on colony fitness. In species in which individual queens vary in fitness, sexu...

Some populations of Pogonomyrmex harvester ants comprise pairs of highly differentiated lineages with queens mating at random with several males of their own and of the alternate lineage. These queens produce two types of diploid offspring, those fertilized by males of the queens' lineage which develop into new queens and those fertilized by males of the other lineage which mostly develop into ...

the object of this study was evaluation of a walking tractor drawn peanut harvester at different conditions of soil moisture content and forward speed and comparing it with manual harvesting. the evaluation factors for peanut harvester were two levels of soil moisture content and three levels of forward speed. the results revealed that the effect of soil moisture content was only significant on...

In this paper, we present and demonstrate a rotational energy harvester with a component-optimised maximum power point tracking (MPPT) circuit for adaptive power conversion. An AM-transmitter and receiver was used to instrument the harvester during operation. Experimental results on the effects of current limiting the harvester and the end-to-end efficiency of the MPPT circuit are shown. Finall...

The object of this study was evaluation of a walking tractor drawn peanut harvester at different conditions of soil moisture content and forward speed and comparing it with manual harvesting. The evaluation factors for peanut harvester were two levels of soil moisture content and three levels of forward speed. The results revealed that the effect of soil moisture content was only significant on...

A tremendous amount of research has been performed on the design and analysis of vibration energy harvester architectures with the goal of optimizing power output; most studies assume idealized input vibrations without paying much attention to whether such idealizations are broadly representative of real sources. These “idealized input signals” are typically derived from the expected nature of ...